Conventionally, an automatic adjustment of a parameter such as a threshold of a sensing level of various sensors such as a photoelectric sensor is performed for each individual sensor. However, in environment, which can be assumed to be identical in a production site, such as a periphery of a production facility, the same line, or a limited area in a factory, a plurality of same kind of sensors of the same product type is generally arranged and used in consideration of unification of a spare part and a usage, or an advantage in a cost.